It is possible to provide an acoustic absorption panel in a form having: (i) a microperforated facing; (ii) a non-perforated backing; and (iii) a cellular core structure extending from the microperforated facing to the non-perforated backing.
Panels of this form provide ‘microperforated panel absorbers’ and may find application as internal walls, ceilings, and partitions in aircraft, ships, trains and buildings. Other applications include use in machinery enclosures.
The microperforated facing could be provided with a number of punched openings, having a diameter of say 0.5 to 1 mm. The cellular core structure could be provided as a hexagonal honeycomb-type array of cells.
By employing microperforated panel absorbers, advantageous acoustic absorption can be provided, without the use of any fibrous materials. Acoustic absorption can be provided at relatively low frequencies and at relatively low weight, which is difficult to achieve with conventional fibrous materials.
The cell depth of the cellular core structure has a profound effect on the acoustic frequencies that can be absorbed. Deep cell depths absorb relatively low frequencies, whereas shallow cell depths absorb relatively high frequencies.
Microperforated panel absorbers are usually highly effective over a relatively narrow waveband corresponding to their cell depth.
It would be advantageous to provide an acoustic absorption panel having improved absorption characteristics, or to at least provide the public with a useful choice.